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My whole life I was told to put up gutters and get water away from your foundation by building effective drainage. The reason was to stop the slab from having different levels of moisture and cracking. My neighbor does the opposite: he waters the ground around his foundation. The reason that he does it is to stop the dirt/clay from separating from the foundation.

Do either of these things matter? We're living in Houston. Our slab-on-grade foundations are built on top of hard black clay (I'm told it's called hardpan). Which of these is the right approach for preventing the need for future foundation repair.

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    When I was a kid, I lived across the street from a lovely older couple. 3-4 mornings a week, he'd be out in his yard watering his trees. He wouldn't just run some water from the hose at the base of the trunk, he used a nozzle to spray down the entire tree, watering all the leaves he could get. Trees don't absorb water through their leaves, so 80-90% of the water he sprayed evaporated long before it ever got to the roots, but it made him happy. Just because your neighbor believes that watering his foundation is the way to go doesn't mean he's right.
    – FreeMan
    May 15, 2022 at 16:49
  • @FreeMan understood, that's why I am asking here. ;) May 15, 2022 at 16:53
  • Considering how many products and businesses there are dedicated to keeping foundations dry, it should seem reasonably obvious to the casual observer what the proper approach is. :)
    – FreeMan
    May 15, 2022 at 16:58
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    @FreeMan Yeah,that,and the distinct lack of fully automated foundation irrigation systems on the market.
    – TooTea
    May 15, 2022 at 17:11
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    I do not think it matters to the concrete but erosion or leakage to the basement or water in the crawl space IS an issue that can cause problems to cure through its life, it becomes more brittle and if the soil supporting it is washed away it will start cracking , the rebar holds things together somewhat but we don’t wast to damage the earth below the foundation or introduce a bunch of moisture into the crawl space and this is why we divert water away from the foundation.
    – Ed Beal
    May 15, 2022 at 19:40

2 Answers 2

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Rant mode: Engage!

Your neighbor is right, but shouldn't be.

He's right in the specific case of Texas and probably much of the SW United States.

Texas in particular has a very clay heavy soil, which expands and contracts more dramatically with varying moisture than other soils. Rather than building foundations that can adequately cope with the forces involved, it is much cheaper for developers to build mostly ordinary slab-on-grade foundations, and make the buyer responsible for perpetual maintenance of the soil's moisture level. Rather than have the house more expensive but a mostly onetime cost, a constant cost of watering is incurred forever.

It is such a problem that foundation repair is a lucrative business in texas. It isn't a matter of if a building will eventually need repair, it's when.

So, it is very common for Texas homeowners to run soaker houses around their houses they are run a slow trickle, all day, every day. Usually pumped from groundwater.

Houston is one of the fastest sinking cities in the world, the only North American city to make the top-10 list. Surely just a coincidence and not partially the result of what I've described above. https://www.weforum.org/agenda/2022/04/coastal-cities-flooding-sinking-climate-change/

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  • I wish this was more sourced and less opinion because these are pretty bold claims, but does it go so far as to say that drainage systems are bad for the soil is also true? I also question whether or not the effects of these drip hoses around foundations are counter-productive if for no other reason then because they encourage trees to root towards the slab. Something we fight very hard to stop. May 15, 2022 at 19:50
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I think the problem soil is gumbo; swells when wet, shrinks when dry. I think you will need a civil engineer to get something beside opinion. I heard the story when I moved to Houston from near Chicago. I never watered the foundation because my house was one of the few in Houston built on very sandy soil ( Spring Creek area). I had no problem in 10 years. It will also make a difference if it is a tension slab, or has piers, or something else. And the "quality" of the builder. My in-laws house started sliding down about a 4% grade and the had to add piers.

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